With the development of display technology, liquid crystal display has become the most commonly used display device. Currently, more and more Light-Emitting Diodes (LED) are used in the liquid crystal display as the backlight source. Moreover, it is hoped that the brightness of the LED can be changed according to different application circumstances. Therefore, the driver of the LED should have the function of brightness adjustment.
Compared with traditional PWM Dimming technology, the Analog Dimming (ADIM) technology has many advantages, such as no noise. However, the voltage range of the dimming signal that is supported by the current analog dimming technology is relatively narrow. In general, the linear dimming can only be performed when the voltage of the dimming signal ranges from 0.5 V to 2.5 V, while the analog dimming cannot be performed when the voltage of the dimming signal ranges from 0 V to 0.5 V or is higher than 2.5 V. however, during display procedures, the voltage of the dimming signal generally ranges from 0 V to 3.3 V. Therefore, the dimming capability of the current analog dimming technology is poor owing to its narrow dimming range.